I'm still confused by the question, and I'm thinking along the same lines as Peter.

What are you trying to play back from? Are you saying you want to plug a hard drive directly into an Uhd tv in a "smart Tv" type of scenario, from within the TV interface maneuver to the hard drive, and hit play?

Typically you put your file to a hard drive, and run it through a computer, hooked up, as Peter said, to the monior (or TV)with some sort of hardware. If the computer/hardware setup can play the file, it will display on what ever you are outputting too, with the assumption you are outputting a proper raster size/frame rate etc that the tv specs can playback. Starting in prores, or DNXHR should be irrelevant at this point.

If it is the above scenario, using a smart tv, then it would depend on the tv specs as to what file types it can play natively. I would be surprise that it could even do a ProRes natively, and would think it was more likely to playback MP4s.

I understand the question perfectly as I just ran into the same problem this evening. The Mac has a setting the TV and thumb drive understand. Render out on a PC and all the formats of UHD do not play on the thumb drive and TV. Looking for simple way to convert to a format the thumb drive and TV understand. The best you can do now is leave it as H264 in standard HD.